Objectives

The purpose of this study was to validate the ScottCare 320 ambulatory blood pressure monitor (ABPM) using both group-level and individual-level validation procedures. The group-level validation followed a modified protocol of the European Hypertension Society's validation protocol. The individual-level validation was conducted to ensure that the monitor is valid from both a research and clinical perspective.

Methods

Participants (n=41) had three simultaneous blood pressure (BP) measurements taken by a trained listener using a mercury column sphygmomanometer and the ScottCare ABPM, which was used to validate the monitor at the group-level and the first half of the individual-level validation (i.e. the difference between the ABPM and auscultatory means for each participant <5 mmHg). The second half of the individual-level validation occurred by examining participants' responses on diary questionnaires taken immediately following the BP measurements (i.e. can extreme or deviant BP values be explained by situational factors).

Results

At the group level, the ABPM passed the criteria laid out by the European Hypertension Society. At the individual level, the difference between the auscultatory and ABPM means was less than 5 mmHg for both systolic and diastolic BP for 36 participants on the initial attempt, and the remaining five on the second attempt. Furthermore, the deviant values were largely attributed to explainable causes, mainly movement.

Conclusion

The ScottCare ABPM is a highly accurate monitor that can be considered valid at both the group and the individual level, and thus appropriate for both clinical and research use.

Objective

Obtaining an accurate blood pressure (BP) reading is vital for diagnosing hypertension. However, BP measures taken in the physician's clinic (CBP) are subject to the 'white coat' bias. Measurements taken outside the office using ambulatory (ABP) and home (HBP) monitoring are superior predictors of cardiovascular diseases compared with CBP, but ABP remains underutilized because of the effort and expense involved. Unfortunately, HBP has limitations, including questionable device validity and patient compliance. Thus, it is important to identify feasible alternative techniques to measure BP in the office that will increase the accuracy of the diagnosis.

Methods

Auscultatory BP was measured in 249 patients in a nonclinical setting by trained technicians (NCBP); on the following day, patients were taken to their physician (CBP). They were also given an HBP monitor, and a 36 h ABP monitoring. Because ABP is considered the gold standard for prediction of cardiovascular disease, these readings were used as the criterion in a statistical model in which CBP, HBP, and NCBP were entered as predictors. The level of agreement between measurements was estimated.

Results

Multiple regression analysis showed that HBP and NCBP (P < 0.001) explained 94 and 87% of the variance in systolic and diastolic ABP, respectively. The agreement between NCBP and ABP was greater than that between CBP and ABP or between HBP.

Conclusion

When ABP monitoring and HBP monitoring are not options, the NCBP at the clinic can avoid the white coat bias and therefore improve diagnosis.